Method for making steel by oxygen blowing



y 1963 T. H. KENNEDY 3,096,173

METHOD FOR MAKING scram. BY OXYGEN BLOWING Filed Feb. 29. 1960 2 Sheets-Sheet 1 July 2, 1963 'r. H. KENNEDY METHOD FOR MAKING STEEL BY OXYGEN BLOWING Filed Feb. 29. 1960 2 Sheets-Sheet 2 INVENTOR TRUMAN H. KENNEDY 191422;

Affarney ma ?IEEEEIEE mv I? %v United States Patent 3,096,173 METHOD FOR MAKING STEEL BY OXYGEN BLOWING Truman H. Kennedy, Pittsburgh, Pa., assignor to United States Steel Corporation, a corporation of New Jersey Filed Feb. 29, 1960, Ser. No. 11,538 1 Claim. (Cl. 75-60) This invention relates to a method and apparatus for making steel by oxygen blowing and more particularly for making steel in a Bessemer converter in which the charge includes molten iron. In the usual Bessemer converter, air is delivered through the bottom of the converter. Steel has also been produced in a converter by blowing air or oxygen across the surface of the bath and also by blowing oxygen generally vertically downwardly on the bath. It is to this latter type of blowing that the present invention relates. Installations for this type of blowing ordinarily require the use of exceptionally long lances and complicated mechanisms for raising and lowering the lance in and out of the vessel at the start and finish of the blow. The distance between the nozzle and the charge is critical when introducing oxygen and in prior practice the adjustment of the lance and its relation to the bath was not easily controlled nor determined. The intense heat generated during the blow also burnt away the end of the lance, thus making adjustment more difficult and also resulted in frequent failures.

It is therefore an object of my invention to provide a converter in which the lance is positioned in the side wall of the vessel with the axis of the lance being substantially vertical during the blow.

Another object is to provide such apparatus in which the height of the lance above the bath may be adjusted during the blow.

A further object is to provide a method of making steel from a charge including molten iron wherein the oxygen is best utilized without damaging the oxygen lance.

These and other objects will be more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is an elevation of the converter;

FIGURE 2 is a view, partly in section, showing the converter positioned for blowing;

FIGURE 3 is a view taken on the line I'lIIII of FIGURE 2;

FIGURE 4 is an enlarged sectional view of the oxygen lance; and

FIGURE 5 is an elevation, with parts broken away, showing the converter in two different positions.

Referring more particularly to the drawings reference numeral 2 indicates a Bessemer converter having the usual opening 4 at one end thereof. Vessel 2 is provided with a lining 6. Trunm'ons 8 mount the vessel 2 for movement about a generally horizontal axis. The vessel is rotated by a motor 10 through gearing 12 connected to trunnion shaft 14. The interior of the vessel is preferably shaped as shown with a flat bottom and is generally circular in cross section. It is a necessary feature of my invention that the shape be such that the level of the hot metal in the vessel will vary as the vessel rotates about its trunnion axis. This may include many different shapes as will be apparent, but it would not include the shape where the vessel interior is spherical in that portion containing the molten bath. Also, according to my invention an oxygen lance 16 is provided through the side wall of the vessel 2. As best shown in FIGURE 4 the lance 16 includes concentrically mounted tubes 18, 20 and 22 preferably made of copper. The tube 18 is open at its lower end and its outer end is connected by a flexible conduit 24 to an oxygen source, not shown. Tube 20 is open at its lower end, but closed at its upper end with an open- 3,096,173 Patented July 2, 1963 ice ing 26 adjacent the upper end. The opening 26 is connected by a flexible conduit 28 to a source of cooling water. The tube 22 is closed at both ends with an outlet 30 adjacent its upper end. The outlet 30 is connected by means of a flexible conduit 32 to a drain. Water passes from the conduit 28 to the space between tubes 18 and 20 to the lower end of the lance'16, returns in the space between tubes 20 and 22 and is discharged through outlet 30 and conduit 32. A plate 34 is welded to the outside of tube 22 adjacent the outlet 30. An opening 36 is provided through the wall of the vessel 2 and an adapter 38 is welded to the shell of the vessel around the opening 36. A flange plate 40 having a tube 42 welded thereto and studs 44 attached thereto is secured to the adapter 38 in any desired manner, such as by means of capscrews, with the tube 42 extending inwardly through opening 36 and with the studs 44 extending outwardly. Openings 46 are provided in the plate 34 for receiving the studs 44. Nuts 48 are threaded on studs 44 on opposite sides of the plate 34 and hold the lance 16 in adjusted position.

The operation of the converter is as follows:

The extension of the lance 16 into the vessel 2 is adjusted to that desired by loosening nuts 48 and moving the plate 34 with the lance 16 thereon to the desired position, after which the nuts 48 are tightened against plate 34. The position of the end of the lance is determined by the size of the charge, the oxygen pressure and various other factors which may change from time to time and may vary from plant to plant. Once positioned the lance remains in adjusted position unless the conditions change. The vessel 2 is rotated to the full line position shown in FIGURE 5 and the vessel charged through opening 4. The charge will be of usual type for this process and in all instances will include molten iron. In addition, scrap and/or other materials may be added. The vessel 2 is then rotated about its horizontal axis to the blowing position shown in FIGURE 2. In this position the axis of the lance 16 is preferably vertical, as shown, but at any rate is substantially vertical. It is preferred that the axis of the oxygen lance be at an angle no greater than 15 to the vertical during the blow. With the vessel so positioned oxygen is supplied to the lance 16 and impinges against the bath. After the charge ignites it is desirable that the distance between the lance and the bath be increased so that there will be greater diffusion of the oxygen. This is accomplished by rotating the vessel 2 about its axis. During the blow the conditions may be such that it will be desired to change the distance between the lance and the bath for other reasons. This also may be done by rotating the vessel 2 about the axis of the trunnion to either raise or lower the level of the bath. For best results the oxygen from the lance should impinge on the middle third of the bath. The position shown in the drawings is particularly desirable. After the blow is completed and the oxygen shut off the vessel 2 is rotated about the axis of the trunnion to discharge the molten steel therefrom in the usual manner.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claim.

I claim:

The method of making steel from a charge including molten iron in a vessel mounted for movement about a generally horizontal axis and having a charging opening at one end and an oxygen lance extending through the wall thereof, which method comprises charging the vessel through said opening, rotating said vessel about its axis to raise the level of molten metal, then delivering oxygen through said lance generally vertically downwardly on the surface of said bath, continuing ilow of oxygen with the 3 t vessel remaining in its last mentioned position until the 2,817,584 Kootz et a1 Dec. 24, 1957 charge ignites, then rotating said vessel to increase the 2,886,308 Boynton May 12, 1959, distance between said metal and lance, shutting ofi said oxygen flow, and then rotating said vessel to discharge FOREIGN PATENTS I molten steeltherefmm- 5 1,030,375 Germany May 22, 1958 Rttttttttt Cttttt it tht fitt tt ttit ttttttt 3135333 $1221 3223 ""3113" E23 i3 13%? UNITED STATES PATENTS O HER REFEREN 1 1737,57? I Burrow Sept. 1, 1903 T 7 CES Morat Mar. 14, 1905 10 Journal of Metals, pp. 742-753, June 1956. 

